Drupal 11 compatibility fixes

src/Form/UserCsvImportForm.php

@@ -210,7 +210,7 @@ class UserCsvImportForm extends FormBase {
       '#type' => 'file',
       '#title' => 'CSV file upload',
       '#upload_validators' => [
-        'file_validate_extensions' => ['csv'],
+        'FileExtension' => ['extensions' => 'csv'],
       ],
     ];